This invention relates to a unique auxiliary gear box configuration incorporated onto a vehicle transmission assembly.
Heavy duty vehicle transmissions typically provide the ability to engage a large number of gear ratios for driving the vehicle. Usually, a main transmission gear box houses a number of gears that are selectively engaged to achieve a particular gear ratio for optimal vehicle performance. An auxiliary or range gear box is often additionally provided to increase the number of available gear ratios. The range gear box typically includes one or more range gears that are selectively engaged by pneumatics to operate the transmission in one of several ranges. Usually the range gear box includes a low range and a high range. For example, the low range is typically associated with the lower gears in the transmission such as first through fifth gear. When the range gear box is shifted into the high range, then the same gears in the transmission main gear box that were used for first through fifth gear are now used for sixth through tenth gear.
Range gear box assemblies are typically bolted onto a transmission main gear box housing. A shaft from the main gear box is coupled to a shaft for the range gear box. Typical range gear box configurations include a range gear box housing, range gears, a piston, solenoids, a range piston housing, and an air regulator.
The air regulator receives air from the vehicle and the solenoids direct the air from the regulator to either of two sides of the piston. The piston controls the selection of the desired range gear. The air regulator and the solenoids are usually bolted onto a mounting bracket which attaches to a housing cover. The solenoids are typically attached to the mounting bracket such that they are located between the range piston housing and the air regulator. The housing cover and range piston housing are attached to the range gear box housing by bolts or screws.
A range piston housing configuration such as this is difficult to package due to the limited space available in the vehicle. Bolting the air regulator to the mounting bracket and orientating it so that it is spaced apart from and in a vertical relationship to the range piston housing takes up a significant amount of room. Also, mounting the solenoids to the bracket so that they are located between the air regulator and the range piston housing takes up valuable space. Additionally, as vehicles move toward using electronic transmission shift systems it is important to be able to monitor the position of the range gears in the range box housing. Current range piston housing configurations make it extremely difficult to package sensors to monitor range selection due to the limited space available.
Thus, it is desirable to have an effective range piston housing assembly that is compact, reduces cost, and reduces the number of parts necessary for the assembly. It would further be desirable to mount a range position sensor to the range piston housing to monitor range gear position for an electronic transmission shift system.